Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757899AbXKZXr7 (ORCPT ); Mon, 26 Nov 2007 18:47:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756776AbXKZXrt (ORCPT ); Mon, 26 Nov 2007 18:47:49 -0500 Received: from mx1.redhat.com ([66.187.233.31]:49163 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756531AbXKZXrs (ORCPT ); Mon, 26 Nov 2007 18:47:48 -0500 Subject: [PATCH 2/3 -v2] mmap: round mmap hint address above mmap_min_addr From: Eric Paris To: linux-kernel@vger.kernel.org Cc: jmorris@namei.org, sds@tycho.nsa.gov, selinux@tycho.nsa.gov, alan@redhat.com, chrisw@redhat.com, hpa@zytor.com, akpm@linux-foundation.org Content-Type: text/plain Date: Mon, 26 Nov 2007 18:47:40 -0500 Message-Id: <1196120860.16779.14.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.3 (2.10.3-7.fc7) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2806 Lines: 92 If mmap_min_addr is set and a process attempts to mmap (not fixed) with a non-null hint address less than mmap_min_addr the mapping will fail the security checks. Since this is just a hint address this patch will round such a hint address above mmap_min_addr. gcj was found to try to be very frugal with vm usage and give hint addresses in the 8k-32k range. Without this patch all such programs failed and with the patch they happily get a higher address. This patch is wrappad in CONFIG_SECURITY since mmap_min_addr doesn't exist without it and there would be no security check possible no matter what. So we should not bother compiling in this rounding if it is just a waste of time. Signed-off-by: Eric Paris --- include/linux/mm.h | 16 ++++++++++++++++ mm/mmap.c | 3 +++ mm/nommu.c | 3 +++ 3 files changed, 22 insertions(+), 0 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 520238c..1b7b95c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -12,6 +12,7 @@ #include #include #include +#include struct mempolicy; struct anon_vma; @@ -513,6 +514,21 @@ static inline void set_page_links(struct page *page, enum zone_type zone, } /* + * If a hint addr is less than mmap_min_addr change hint to be as + * low as possible but still greater than mmap_min_addr + */ +static inline unsigned long round_hint_to_min(unsigned long hint) +{ +#ifdef CONFIG_SECURITY + hint &= PAGE_MASK; + if (((void *)hint != NULL) && + (hint < mmap_min_addr)) + return PAGE_ALIGN(mmap_min_addr); +#endif + return hint; +} + +/* * Some inline functions in vmstat.h depend on page_zone() */ #include diff --git a/mm/mmap.c b/mm/mmap.c index 938313c..f4cfc6a 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -912,6 +912,9 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, if (!len) return -EINVAL; + if (!(flags & MAP_FIXED)) + addr = round_hint_to_min(addr); + error = arch_mmap_check(addr, len, flags); if (error) return error; diff --git a/mm/nommu.c b/mm/nommu.c index 35622c5..b989cb9 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -829,6 +829,9 @@ unsigned long do_mmap_pgoff(struct file *file, void *result; int ret; + if (!(flags & MAP_FIXED)) + addr = round_hint_to_min(addr); + /* decide whether we should attempt the mapping, and if so what sort of * mapping */ ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/